Richard Widmark, whose six-decade film career was sparked by a memorable portrayal as a cackling hood, died March 24 at his home in Roxbury, CT. He was 93.

Mr. Widmark would go one to play a wide variety of characters over the ensuing years — including an iconic film noir performance as a nervous London con artist in Jules Dassin's "Night and the City" — but for the first few years of his Hollywood tenure he was defined by Tommy Duo, a psychopathic gangster who was most frightening when he tittered, in Henry Hathaway's 1947 documentary-like noir "Kiss of Death."

Mr. Widmark achieved instant film immortality in a chilling scene in which he ties the mother of a squealer to her wheelchair and shoves her down the stairs.

20th Century Fox boss Darryl F. Zanuck had insisted Mr. Widmark be cast in the role, and after it made such an impression — the actor won an Oscar nomination — the mogul insisted on more of the same, much to the actor's chagrin. In the next few years, he plays psychos and killers in "The Street With No Name," "Yellow Sky" and "Road House." With time, he proved himself in more typical leading man parts, such as a physician who is frantically trying to fend off an outbreak of Bubonic Plague, requiring him to pursue bad guys Zero Mostel and Jack Palance, in Elia Kazan's "Panic in the Streets."

But even as he played the hero, Mr. Widmark brought an ambiguous tension to his characters. Part of this was due to his distinctive physical appearance. Lean, pale and shifty-looking, with tightly drawn features, he was not conventionally handsome. Critics commented that he seemed to personify the neuroses and uncertainties of the post-Atomic age. The people he played were rarely paragons of virtue, but, through their sweaty struggles to define themselves, Mr. Widmark made them engrossing and even sympathetic figures.

His best role, in fact, was arguably his least likable. In "Night and the City" (1950), as Harry Fabian, two-bit hustler in London's underground (he is memorable described as "an artist without an art"), he cheats and deceives everyone around him in myriad ways, ceaselessly running every which way in order to "be somebody." Yet, until his predictably pathetic end, he provokes the sort of concern a misguided child might. Richard Widmark was born was born on Dec. 26, 1914 in Sunrise, MN. He developed a habit of attending films as a young boy. Moving to a succession of small towns in the Midwest, he excelled at public speaking. He attended Lake Forest College in Illinois, and then spent two years as an instructor in the Lake Forest drama department.

Moving to New York, he quickly used his vocal powers to establish himself as a top radio actor. His stage career was short. Excluded from service in World War II because of a perforated eardrum, he appeared in a succession of five Broadway shows in the mid-1940s, beginning with the hit comedy Kiss and Tell in 1943. He acted in William Saroyan's Get Away Old Man after that, then Trio, a play that was closed by the License Commissioner after 67 performances, the New York Times reported, because it dealt with lesbianism.

Luther Davis' Kiss Them for Me and S.N. Behrman's Dunnigan's Daughter followed, both in 1945 neither of them hits. Soon after, his Hollywood star rose and Mr. Widmark never returned to Broadway.

He was married to Jean Hazlewood for 45 years until her death in 1997. He is survived his second wife, Susan Blanchard, and his daughter, Anne Heath Widmark.